JP4651986B2 - Information embedding device and program - Google Patents

Description

  The present invention relates to an information embedding device, an embedded information extracting device, an information embedding method, an embedded information extracting method, and information that can extract information embedded in the printed material without performing top / bottom determination even when the printed material is read upside down. embedding program, an embedded information extraction program, and a recording medium.

  Information other than normal images and text information (hereinafter referred to as “secret information”) such as tampering verification information may be embedded in the printed matter. Generally, a printed matter of an image or a character basically has a top and bottom, and the above information is also given a top and bottom corresponding to the image or the character.

  The technique disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-034093: “Multi-directional Printed Material”) is applied to a printed material in which the printed content can be easily confirmed from the top and the left and right directions. By printing the top and bottom target printing, normal printing and reverse printing, it is possible to read from both `` top '' and `` ground '', you can check the normal printing with the `` ground '' direction of the paper facing you, and the paper The paper is printed with printed contents such as symbols, letters, numbers, sentences, maps, etc. that can be checked for reverse printing with the “heaven” direction facing the other.

  The technology disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 05-191585: “Character Information Reading Device”) is applied to a document information reading device having a function of automatically rotating the paper in the paper feeding direction. The direction of the document is determined by comparing the number of document information in each area when divided into upper and lower or left and right areas, and if it is upside down, the direction of the document is rotated.

The technique disclosed in Patent Document 3 (Japanese Patent Laid-Open No. 09-223225: “Image processing apparatus capable of detecting the orientation of a read image”) uses a specific pattern to determine whether the image is upside down.
JP2003-034093 JP 05-191585 JP 09-223225 A

  However, in Patent Document 1, it is necessary to embed the same contents in a printed matter a plurality of times in order to enable reading confidential information even if the head is reversed upside down or left and right, and the amount of information that can be embedded is reduced accordingly. Further, in Patent Documents 2 and 3, when a printed matter is read for the purpose of extracting secret information, it takes time to determine whether to flip the image upside down or horizontally, so that it takes time to extract the secret information and the processing amount increases. There is a problem.

An object of the present invention, top and bottom of the forward and reverse or left and right reversal of decision that can be processed information embedding device creates the image data can be extracted information embedded without performing is to provide a contact and program.

An information embedding device according to the present invention is an information embedding device for embedding information in a processing target image, and includes an image dividing unit that divides the processing target image into a plurality of regions, and a plurality of dot patterns added to the regions. An information embedding unit that embeds information in the processing target image, and the information embedding unit is symmetric with respect to the scanning direction in another region corresponding to the region when the processing target image is reversed upside down. The plurality of dot patterns are added.

According to the present invention, it is possible to generate a processing target image that can acquire embedded information without checking the rotation angle.

  Hereinafter, embodiments of an information embedding device, an information embedding method, an information embedding program, and a recording medium will be described with reference to the drawings. In the following embodiment, a case where falsification verification information is embedded as confidential information in a printed material will be described as an example.

  FIG. 1 is a functional block diagram of an information embedding device (an alteration verification information embedding device) that can create a verifiable printed material even when the printed material is read upside down. In FIG. 1, the information embedding apparatus 1 </ b> A includes a processing target image acquisition unit 11, an image division unit 12, a falsification verification information acquisition unit 13, a falsification verification information information embedding unit 14, and a printing unit 15. It is configured.

  FIG. 2 is an actual configuration diagram showing an information embedding device corresponding to the information embedding device 1A of FIG. An information embedding device 2A shown in FIG. 2 includes a CPU 21, a memory (consisting of ROM, RAM, etc.) 22, an image reading device (image scanner, etc.) 23, and an image printing device (printer) 24. A method (falsification verification information embedding method) can be implemented.

  In FIG. 2, the memory 22 stores a processing target image acquisition program, an image division program, a falsification verification information acquisition program, a falsification verification information information embedding program, and a print program. Each step of the information embedding method of the present invention can be executed.

  FIG. 3A shows a printed matter to be processed (processing target image OG), and FIG. 3B shows an image (post-processing image PG) after falsification verification information is embedded using a dot pattern. 3C shows a partially enlarged view of FIG. 3B.

  First, the processing target image acquisition unit 11 acquires the processing target image OG of FIG. The image dividing unit 12 divides the processing target image OG into a plurality (two in this embodiment) of regions by a dividing line passing through the center thereof. FIG. 4 shows an example in which the processing target image OG is divided into an upper region 31 and a lower region 32 by a dividing line (horizontal line) 33 passing through the center C thereof.

  The falsification verification information acquisition unit 13 creates falsification verification information corresponding to the upper region 31 and the lower region 32 according to the following procedure.

  5 (A), (B-1), (B-2), (C-1), (C-2), (D-1), (D-2), (E-1), (E -2) shows an example of a procedure for acquiring falsification verification information corresponding to the upper region 31 and the lower region 32.

  First, the upper area 31 shown in FIG. 5 (A) is further divided into a plurality of rectangles, and when a stroke of a character is included in each rectangle as shown in FIG. Is not included, a code “0” is assigned to create a code matrix 411. Then, the inside of the code matrix 411 is raster-scanned from the upper left to the lower right as shown in FIG. 5 (B-1), and consists of “0” and “1” as shown in FIG. 5 (C-1). A code string 421 is obtained, and this code string 421 is used as an input, and calculation is performed by the hash function 43 as shown in FIG. 5D-1 and obtained as upper stage embedded information 441 as shown in FIG. 5E-1 To do.

  Similarly, the lower area 32 shown in FIG. 5A is divided into a plurality of rectangles, and a character stroke is included in each rectangle as shown in FIG. 5B-2. Is not included, a code “0” is assigned to create a code matrix 412. Then, raster scanning is performed from the lower right to the upper left in the code matrix 412 as shown in FIG. 5B-2, and it consists of “0” and “1” as shown in FIG. 5C-2. A code string 422 is obtained, and the code string 422 is input to perform calculation by the hash function 43 as shown in FIG. 5D-2 to obtain lower-stage embedded information 442 shown in FIG. 5E-2.

  As described above, by performing raster scanning so that the upper area and the lower area are point-symmetric with respect to the center point C, it is possible to perform encoding with the same scanning even if the information is read in the upside down direction.

  The information embedding unit 14 embeds the upper stage embedding information 441 and the lower stage embedding information 442 acquired by the information acquiring unit 13 in the upper stage area 31 and the lower stage area 32.

  In the present embodiment, information is embedded in the upper region 31 and the lower region 32 using two types of dot patterns that do not change even if the top and bottom are reversed as shown in FIGS. In practice, the tampering verification information information embedding unit 14 embeds embedded information in each of the rectangles in the upper region 31 and the lower region 32.

  FIG. 7 shows the scanning direction when the upper stage embedding information 441 is embedded in the upper stage area 31 and the lower stage embedding information 442 is embedded in the lower stage area 32. By embedding embedded information by scanning as shown in FIG. 7, even if the processing target image OG is read upside down, extraction of embedded information as described later becomes possible with the same scanning.

  FIG. 8 shows a superimposed image (processed image PG) as a result of embedding the embedded information with two types of dot patterns.

  The printing unit 15 in FIG. 1A prints the superimposed image (processed image PG) generated by the information embedding unit 14.

  As described above, it is possible to create a printed matter from which information for verifying tampering can be extracted without performing top-and-bottom determination even when read upside down.

  FIG. 9 is a functional block diagram of an information embedding device (an alteration embedding information embedding device) that can create a verifiable printed material even when the printed material is read upside down and horizontally reversed. In FIG. 9, the information embedding device 1B is basically the same as the information embedding device 1A shown in FIG. However, in this embodiment, the information embedding device 1B includes the processing target image acquisition unit 11, the image division unit 12, the alteration verification information acquisition unit 13, the alteration verification information information embedding unit 14, and the printing unit 15. It is configured to include an image pattern specifying unit 16.

  FIG. 10 is an actual configuration diagram showing an information embedding device corresponding to the information embedding device 1B of FIG. The information embedding device 2B in FIG. 10 is similar to the information embedding device 2A in FIG. 2 in that a CPU 21, a memory (consisting of ROM, RAM, etc.) 22, an image reading device (image scanner, etc.) 23, and an image printing device (printer) 24 And an information embedding method (falsification verification information embedding method) of the present invention can be implemented. However, in FIG. 10, in addition to the processing target image acquisition program, the image division program, the falsification verification information acquisition program, the falsification verification information information embedding program, and the print program, the memory 22 includes an image pattern designation program. Are stored, and each program can execute each step of the information embedding method of the present invention.

  The printed matter to be processed (processing target image OG) is the same as that shown in FIG. 3A, and the image after the alteration verification information is embedded using the dot pattern (post-processing image PG) is shown in FIG. it is the same as those shown in 3 (B).

  First, the processing target image acquisition unit 11 acquires the processing target image OG of FIG. The image dividing unit 12 divides the processing target image OG into a plurality of (four in this embodiment) regions by a dividing line passing through the center thereof. In FIG. 11, the processing target image OG is divided into an upper right region 31A, an upper left region 31B, a lower left region 31C, and a lower right region 31D by dividing lines (horizontal and vertical lines) 33A and 33B passing through the center C. An example is shown.

  The falsification verification information acquisition unit 13 creates falsification verification information corresponding to the upper right region 31A, the upper left region 31B, the lower left region 31C, and the lower right region 31D according to the following procedure.

  12 (A), (B-1), (B-2), (B-3), (B-4), (C-1), (C-2), (C-3), (C -4), (D-1), (D-2), (D-3), (D-4), (E-1), (E-2), (E-3), (E-4) ) Shows an example of a procedure for acquiring falsification verification information corresponding to the upper right region 31A, the upper left region 31B, the lower left region 31C, and the lower right region 31D.

  First, the upper right region 31A shown in FIG. 12A is further divided into a plurality of rectangles, and when a stroke of a character is included in each rectangle as shown in FIG. Is not included, a code “0” is assigned to create a code matrix 41A. Then, raster scanning is performed from the upper right to the lower left in the code matrix 41A as shown in FIG. 12 (B-1), and a code consisting of “0” and “1” as shown in FIG. 12 (C-1). A sequence 42A is obtained, and the code sequence 42A is input to perform an operation by the hash function 43 as shown in FIG. 12D-1 and obtained as upper right region embedded information 44A as shown in FIG. 12E-1. To do.

  Similarly, the upper left region 31B shown in FIG. 12A is divided into a plurality of rectangles, and a character stroke is included in each rectangle as shown in FIG. 12B-2. Is not included, a code “0” is assigned to create a code matrix 41B. Then, the code matrix 41B is raster-scanned from the upper left to the lower right as shown in FIG. 12B-2, and consists of “0” and “1” as shown in FIG. 12C-2. A code string 42B is obtained, and this code string 42B is used as an input to perform calculation by the hash function 43 as shown in FIG. 12D-2 to obtain the upper left area embedded information 44B shown in FIG. 12E-2. .

  Similarly, the lower left region 31C and the lower right region 31D shown in FIG. 12A are also divided into a plurality of rectangles, and as shown in FIGS. 12B-3 and B-4, each rectangular region is divided. “1” and “0” are assigned to generate code matrices 41C and 41D. Then, raster scanning is performed from the lower left to the upper right in the code matrix 41C, and raster scanning is performed from the lower right to the upper left in the code matrix 41D, as shown in FIGS. 12C-3 and 12C-4. Code sequences 42C and 42D composed of “0” and “1” are obtained, and the code sequences 42C and 42D are input, and the calculation by the hash function 43 is performed as shown in FIGS. 12D-3 and 12D-4. Then, the lower left area embedding information 44C and the lower right area embedding information 44D shown in FIGS. 12E-3 and E-4 are acquired.

  In this way, the upper right area 31A, the upper left area 31B, the lower left area 31C, and the lower right area 31D are raster-scanned so as to be symmetric with respect to the center point C, so that the top and bottom are reversed at the stage of reading information. Even if it is reversed or left and right reversed, it is possible to encode with the same scanning.

  The image pattern designating unit 16 sets the bit “0” and the bit “1” when the information created by the information acquiring unit 13 is embedded in the upper right region 31A, the upper left region 31B, the lower left region 31C, and the lower right region 31D. Each image pattern to be represented is determined.

  13A-1 and 13A-2 show a pattern of embedded bits “0” and a pattern of bit “1” in the upper right region 31A and the lower left region 31C, and FIGS. A-2) shows a pattern of bit “0” and a pattern of bit “1” embedded in the upper left region 31B and the lower left region 31C. In the present embodiment, the bit pattern to be used can be designated by the image pattern designating unit 16, but a bit pattern to be used in advance may be set without providing this. Further, the image embedding device 16 may be provided in the information embedding device 1A shown in FIGS.

  In the information embedding means 14, the upper right area embedding information 44A, the upper left area embedding information 44B, the lower left area embedding information 44C, the lower right area embedding information 44D acquired by the information acquisition means 13, the upper right area 31A, and the upper left area It is embedded in 31B, lower left region 31C, and lower right region 31D. The falsification verification information information embedding unit 14 embeds the embedded information in each of the rectangles of the upper right region 31A, the upper left region 31B, the lower left region 31C, and the lower right region 31D.

  FIG. 14 shows the scanning direction when embedding information 44A, 44B, 44C, 44D is embedded in each of the areas 31A, 31B, 31C, 31D. By embedding the embedded information by scanning as shown in FIG. 13, even if the processing target image OG is read upside down or read horizontally, it is embedded in the same scan as described later. Can be extracted.

  The printing unit 15 in FIG. 9 prints the superimposed image (processed image PG) generated by the information embedding unit 14.

  As described above, it is possible to create a printed material from which information for verifying tampering can be extracted without determining whether the image is read upside down or without being turned upside down.

  Embodiments of an embedded information extraction device, an embedded information extraction method, an embedded information extraction program, and a recording medium that can be verified even when a printed material is read upside down will be described with reference to FIGS. In the following embodiment, a case where secret information embedded in a printed material is falsification verification information will be described as an example.

  FIG. 15 is a functional block diagram of an embedded information extraction apparatus (information extraction apparatus for tampering verification). In FIG. 15, the embedded information extracting apparatus 6A includes an information extraction target image obtaining unit 61, an image dividing unit 62, an embedded information extracting unit 63, and an information output unit 64.

  FIG. 16 is an actual configuration diagram showing an information embedding device corresponding to the information embedding device 6A of FIG. The information embedding device 7A shown in FIG. 16 includes a CPU 71, a memory (consisting of ROM, RAM, etc.) 72, an image reading device (image scanner, etc.) 73, and an image output device (printer, display) 74. An information embedding method (falsification verification information embedding method) can be implemented.

  In FIG. 16, an information extraction target image acquisition program, an image segmentation program, a reference information acquisition program, an embedded information extraction program, and an information output program are stored in the memory 72. it is possible to perform the steps of the information extraction methods.

  The image reading unit 61 reads the printed material to be verified as an image, and obtains a processing target image (indicated by OG ′ in FIG. 3).

  The image region dividing means 62 is divided into two regions (in FIG. 4, an upper region 31 and a lower region 32) by a dividing line 33 passing through the center C of the processing target image OG ′ in the same manner as shown in FIG. ).

  In the information extraction means 63, information for tampering verification is embedded from each area by raster scanning the upper area 31 from the upper left to the lower right, and the lower area 32 'from the lower right to the upper left. The information of the code “0” and the code “1” is extracted.

  By scanning in this way, even if the processing target image OG ′ is upside down in the processing stage by the image reading means 61, that is, the upper area 31 is the lower area 32 in the processed image PG, and the upper area 32 ′. Even if it is the lower region 31 in the processed image PG, since the scanning direction does not change, the embedded information can be reliably extracted (corrected).

  As described above, even if the printed material is read upside down, the embedded information can be reliably extracted without determining the top and bottom.

  When verifying the tampering of the printed matter, the verification information (hash value) is calculated in each area in the same manner as when the printed matter is created, and this hash value is compared with the original hash value. If it does not match, it can be determined that there has been falsification, and the information output means 64 outputs the verification result to a display or the like.

  In the above embodiment, an example in which the dividing line of the processing target images OG and OG ′ is a horizontal line has been described. However, as shown in FIG. 17, a dividing line (vertical line) 37 passing through the center C of the image is used. It is also possible to divide into two right areas 35 and left areas 36, and to scan each area in the direction as shown in the figure.

  Embodiments of an embedded information extraction device, an embedded information extraction method, an embedded information extraction program, and a recording medium that can be verified even when a printed matter is read upside down or horizontally reversed will be described with reference to FIGS. In the following embodiment, a case where secret information embedded in a printed material is falsification verification information will be described as an example.

  FIG. 18 is a functional block diagram of the embedded information extraction device (information alteration device for falsification verification). In FIG. 18, the embedded information extracting device 6B includes an information extraction target image obtaining unit 61, an image dividing unit 62, an embedded information extracting unit 63, an information output unit 64, and an image pattern designating unit 65. ing.

  FIG. 19 is an actual configuration diagram showing an information embedding device corresponding to the information embedding device 6B of FIG. The information embedding device 7B in FIG. 19 is similar to the information embedding device 7A in FIG. 16, with a CPU 71, a memory (consisting of ROM, RAM, etc.) 72, an image reading device (image scanner, etc.) 73, and an image output device (printer, display). 74, and can implement the information embedding method of the present invention (falsification verification information embedding method).

  In FIG. 19, the memory 72 stores an information extraction target image acquisition program, an image division program, a reference information acquisition program, an embedded information extraction program, an information output program, and an image pattern designation program. However, each step of the information extraction method of the present invention can be executed.

  The image reading unit 61 reads the printed material to be verified as an image, and obtains a processing target image (for example, indicated by OG ′ in FIG. 3).

  The image area dividing means 62 is a method similar to that shown in FIG. 12A, and the processing object image OG ′ is divided into four areas (upper right in FIG. 11) by a horizontal dividing line 37A and a vertical dividing line 37B passing through the center C. Area 35A, upper left area 35B, lower left area 34C, and lower right area 35D).

  In the information extraction means 63, information for falsification verification is obtained from each of the above areas, the upper right area 35A is from the upper right to the lower left, the upper left area 35B is from the upper left to the lower right, and the lower left area 35C is from the lower left to the upper right. The lower right area 35D is raster-scanned from the lower right to the upper left, and the information of the embedded code “0” and code “1” is extracted. In FIG. 21, the extracted information is indicated by 45A, 45B, 45C, 45D.

  By scanning in this way, even if the processing target image OG ′ is upside down or horizontally reversed at the processing stage by the image reading means 61, as shown in FIG. 21, the upper right, upper left, lower left, right Since the scanning direction in each region below does not change, the embedded information can be reliably extracted.

  As described above, for example, even if a printed material is read upside down, the embedded information is surely extracted without making a top / bottom judgment or without making a rotation judgment even if it is read horizontally reversed as shown in FIG. It becomes possible to do.

  When verifying the tampering of the printed matter, the verification information (hash value) is calculated in each area in the same manner as when the printed matter is created, and this hash value is compared with the original hash value. If it does not match, it can be determined that there has been falsification, and the information output means 64 outputs the verification result to a display or the like.

It is a figure which shows an example of the functional block diagram of an information embedding apparatus. It is an actual block diagram which shows the information embedding apparatus corresponding to the information embedding apparatus of FIG. (A) is a diagram showing a printed matter to be processed, (B) is a diagram showing an image after falsification verification information is embedded using a dot pattern, and (C) is a partially enlarged view of (B). FIG. It is a figure which shows the example which divided | segmented the process target image into the upper stage area | region and the lower stage area | region with the horizontal line which passes along the center. (A), (B-1), (B-2), (C-1), (C-2), (D-1), (D-2), (E-1), (E-2) () Is a diagram showing a procedure for acquiring falsification verification information corresponding to the upper and lower regions. (A), (B) is a figure which shows two types of dot patterns which do not change even if it turns upside down. It is a figure which shows the scanning direction when upper stage embedding information is embedded to an upper stage area | region, and lower stage embedding information is embedded to a lower stage area | region. It is a figure which shows the superimposed image (processed image) as a result of embedding embedding information by two types of dot patterns. Is a diagram illustrating an example of a functional block diagram of the information embedding apparatus. It is an actual block diagram which shows the information embedding apparatus corresponding to the information embedding apparatus of FIG. It is a figure which shows the example which divided | segmented the process target image into four area | regions with the horizontal line and vertical line which pass along the center. (A), (B-1), (B-2), (B-3), (B-4), (C-1), (C-2), (C-3), (C-4) ), (D-1), (D-2), (D-3), (D-4), (E-1), (E-2), (E-3), (E-4) FIG. 12 is a diagram illustrating a procedure for acquiring falsification verification information corresponding to the four areas in FIG. 11. (A-1), (A-2), (B-1), and (B-2) are diagrams showing two types of dot patterns that do not change even if they are reversed upside down or horizontally. . It is a figure which shows the scanning direction when embedding information is embedded in four area | regions. It is a functional block diagram of an embedded information extraction device. It is an actual block diagram which shows the information embedding apparatus corresponding to the information embedding apparatus 6 of FIG. It is a figure which shows the example of a division | segmentation of a screen when the division line of a process target image is made into a perpendicular line. It is a functional block diagram of an embedded information extraction device. It is an actual block diagram which shows the information embedding apparatus corresponding to the information embedding apparatus of FIG. It is a figure which shows the mode at the time of reading a document in the horizontal direction. It is a figure which shows the scanning direction in the case of extracting the embedding information of 4 area | regions at the time of embedding information extraction.

Explanation of symbols

1A, 1B, 2A, 2B Information embedding device 6A, 6B, 7A, 7B Embedding information extracting device 11 Processing target image acquiring means 12 Image dividing means 13 Tampering verification information acquiring means 14 Tampering verification information information embedding means 15 Printing means 16 Image pattern designating means 21, 71 CPU
22, 72 Memory 23, 73 Image reading device 24 Image printing device 31 Upper area 31A Upper right area 31B Upper left area 31C Lower left area 31D Lower right area 32 Lower area 33, 37, 33A, 33B Dividing line 33A Horizontal dividing line 33B Vertical dividing line 35 Right area 36 Left area 43 Hash function 44A Upper right area embedding information 44B Upper left area embedding information 44C Lower left area embedding information 44D Lower right area embedding information 45A, 45B, 45C, 45D Extraction information 61 Information extraction target image acquisition means 62 Image division means 63 Embedding information extracting means 64 Information extracting means 74 Image output device 411, 412 Code matrix 421, 422 Code string 441 Upper stage embedded information 442 Lower stage embedded information OG, OG ′ Processing target image C Image center

Claims (12)

An information embedding device for embedding information in a processing target image,
Image dividing means for dividing the processing target image into a plurality of regions;
Information embedding means for embedding information in the processing target image by adding a plurality of dot patterns for each region;
With
The information embedding unit adds the plurality of dot patterns for each of the regions in a scanning direction that is symmetric with respect to a scanning direction in another region corresponding to the case where the processing target image is inverted upside down. An information embedding device. The information embedding apparatus according to claim 1, wherein the information embedding unit adds a dot pattern for each region in a scanning direction from each corner of the processing target image toward a central portion of the processing target image.   The information embedding apparatus according to claim 1, wherein the image dividing unit divides the acquired processing target image based on a center line of the processing target image.   The information embedding apparatus according to claim 1, wherein the image dividing unit divides the acquired processing target image based on two center lines orthogonal to each other. 5. The information embedding apparatus according to claim 1, wherein the information embedding unit adds a dot pattern for each of the areas in a direction symmetrical to a dot pattern added to another area.   6. The information embedding apparatus according to claim 1, wherein the dot pattern is a dot pattern corresponding to image information of each area to be added. On the computer,
An image dividing step for dividing the processing target image into a plurality of regions;
An information embedding step of embedding information in the processing target image by adding a plurality of dot patterns for each region;
A program for executing
In the information embedding step, the plurality of dot patterns are added for each of the regions in a scanning direction that is symmetric with respect to a scanning direction in another region corresponding to the case where the processing target image is inverted upside down. Program to do. The program according to claim 7, wherein the information embedding step adds a dot pattern for each region in a scanning direction from each corner of the processing target image toward a central portion of the processing target image.   The program according to claim 7 or 8, wherein the image dividing step divides the acquired processing target image based on a center line of the processing target image.   The program according to claim 7 or 8, wherein the image dividing step divides the acquired processing target image based on two center lines orthogonal to each other. The program according to any one of claims 7 to 10, wherein the information embedding step adds a dot pattern in each of the areas in a direction symmetrical to a dot pattern added to another area.   12. The program according to claim 7, wherein the dot pattern is a dot pattern corresponding to image information of each area to be added.